Spinal fusion surgeries that use bone graft material to promote specific vertebrae to grow together into a solid and stable construct are a common method of treating patients with severe back pain. In posterior lumbar interbody fusion (PLIF), damaged disk material is removed and one or more implants are inserted posteriorly to promote bone growth from vertebral body to vertebral body to bridge the gap left by the removed material.
A larger implant better fills the intervertebral space and distributes compressive loads. A larger implant also reduces the need for multiple implants, which may require multiple approaches to insertion and placement. However, Minimally Invasive Surgery (MIS) necessitates the use of less invasive techniques that use smaller access portals to perform the fusion that limit the size of implant that can be used.
An example of this is Transforaminal Posterial Lumbar Interbody Fusion (T-PLIF), which is a variation of the PLIF technique. In this procedure, an implant is inserted through a unilateral or bilateral posterior approach. The T-PLIF technique avoids damage to the nerve structures such as the dura, cauda equine, and the nerve root, but the transforaminal window through which the procedure is performed is limited making the insertion and positioning of the implant difficult.
Thus what is needed is an implant that can suitably fill the intervertebral space but can be inserted and positioned through a small access portal, such as the transforaminal window used in a T-PLIF procedure.